CVE-2026-53243 (GCVE-0-2026-53243)

Vulnerability from cvelistv5 – Published: 2026-06-25 08:39 – Updated: 2026-06-25 08:39
VLAI
Title
rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()
Summary
In the Linux kernel, the following vulnerability has been resolved: rseq: Fix using an uninitialized stack variable in rseq_exit_user_update() There is an bug in which an uninitialized stack variable is used in rseq_exit_user_update() as reported by syzbot: BUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline] The local variable: struct rseq_ids ids = { .cpu_id = task_cpu(t), .mm_cid = task_mm_cid(t), .node_id = cpu_to_node(ids.cpu_id), }; According to the C standard, the evaluation order of expressions in an initializer list is indeterminately sequenced. The compiler (Clang, in this KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before* `ids.cpu_id` is initialized with `task_cpu(t)`. This is fixed by moving the assignment of ids.node_id outside the structure initialization.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: d242126fd21ab8f1631fdbc8589e43a9d4229f3b , < e12d20a63b61aaf9de4772effccf42cc9a003e58 (git)
Affected: 82f572449cfe75f12ea985986da60e11f308f77d , < 6d99479799c69c3cb588fcda19c81d8f61d64ecd (git)
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Linux Linux Affected: 7.0.10 , < 7.0.13 (semver)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrseq: Fix using an uninitialized stack variable in rseq_exit_user_update()\n\nThere is an bug in which an uninitialized stack variable is used in\nrseq_exit_user_update() as reported by syzbot:\n\nBUG: KMSAN: kernel-infoleak in rseq_set_ids_get_csaddr include/linux/rseq_entry.h:502 [inline]\n\nThe local variable:\n\n\tstruct rseq_ids ids = {\n\t\t.cpu_id\t = task_cpu(t),\n\t\t.mm_cid\t = task_mm_cid(t),\n\t\t.node_id = cpu_to_node(ids.cpu_id),\n\t};\n\nAccording to the C standard, the evaluation order of expressions in an\ninitializer list is indeterminately sequenced. The compiler (Clang, in\nthis KMSAN build) evaluates `cpu_to_node(ids.cpu_id)` *before*\n`ids.cpu_id` is initialized with `task_cpu(t)`.\n\nThis is fixed by moving the assignment of ids.node_id outside the\nstructure initialization."
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      "providerMetadata": {
        "dateUpdated": "2026-06-25T08:39:37.794Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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          "url": "https://git.kernel.org/stable/c/6d99479799c69c3cb588fcda19c81d8f61d64ecd"
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      ],
      "title": "rseq: Fix using an uninitialized stack variable in rseq_exit_user_update()",
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    "cveId": "CVE-2026-53243",
    "datePublished": "2026-06-25T08:39:37.794Z",
    "dateReserved": "2026-06-09T07:44:35.393Z",
    "dateUpdated": "2026-06-25T08:39:37.794Z",
    "state": "PUBLISHED"
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  }
}


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